What does that even mean? Is he the well of all knowledge on the matter?Huh I just watched MKBHD video about the event and he said pretty much everyone he knew using some kind of SD card.
Professional photographers use them, but in dual slot cameras as a backup. Most professional cameras use a dual slot system of CF + SD, CF being the faster by far.
Anyway, the point is moot as I have never met a single person shooting in a professional capacity that doesn’t use a card reader or 2.
The slot is not going to see major use by professionals, but casual users will love it.